Operational amplifiers have long been used as comparators, audio amplifiers, filters, etc. An operational amplifier is basically a differential amplifier that amplifies the difference between two inputs. One input has a positive effect on the output signal of the amplifier, and the other input has a negative effect on the output signal. Both inputs act on the output signal simultaneously, and the output signal is the sum of both inputs. Accordingly, if both inputs are equal, then the output signal is ideally zero.
An electronic system incorporating an operational amplifier is frequently required to operate with a large dynamic range. Typically, this requirement means that the electronic system must be able to function properly with signal levels ranging from a very small signal level to a very large signal level. In order for the electronic system to operate well when the signal level is small, the electronic system must introduce very little electronic noise. On the other hand, in order to handle large signals, the electronic system must behave in a very linear manner so as not to introduce any distortion into its output signal.
The present invention is directed to an operational amplifier with a wide dynamic range. Because operational amplifiers are used in a wide variety of electronic systems, the operational amplifier of the present invention is useful in many applications.